Liquid ejection head and recording apparatus

Abstract

A first flow path member of a liquid ejection head includes a plurality of pressurizing chambers respectively connected to a plurality of ejection holes, a plurality of first individual flow paths and a plurality of second individual flow paths which are respectively connected to the plurality of pressurizing chambers, and a first common flow path connected in common to the plurality of first individual flow paths and the plurality of second individual flow paths. The pressurizing chamber, the first individual flow path, the first common flow path, and the second individual flow path configure an annular flow path. When T 0 denotes a resonance period of the pressurizing chamber and T 1 denotes a time required for a pressure wave to circulate once around the annular flow path, a decimal place value of T 1 /T 0 is ⅛ to ⅞.

The invention claimed is: 
     
       1. A liquid ejection head comprising:
 a flow path member comprising
 a plurality of ejection holes, 
 a plurality of pressurizing chambers respectively connected to the plurality of ejection holes, 
 a plurality of first flow paths respectively connected to the plurality of pressurizing chambers, 
 a plurality of second flow paths respectively connected to the plurality of pressurizing chambers, and 
 a third flow path connected in common to the plurality of first flow paths and the plurality of second flow paths; and 
 
 a plurality of pressurizing units for respectively pressurizing a liquid inside the plurality of pressurizing chambers, wherein 
 in one of the plurality of first flow paths and one of the plurality of second flow paths, which are connected to one of the plurality of pressurizing chambers, 
 a decimal place value of T 1 /T 0  is ⅛ to ⅞, where T 0  denotes a resonance period of the one of the plurality of pressurizing chambers and T 1  denotes a time required for a pressure wave to circulate once around an annular flow path sequentially passing through the one of the plurality of pressurizing chambers, the one of the plurality of first flow paths, the third flow path, and the one of the plurality of second flow paths. 
 
     
     
       2. The liquid ejection head according to  claim 1 , wherein
 the decimal place value of T 1 /T 0  is ¼ to ¾. 
 
     
     
       3. The liquid ejection head according to  claim 1 , wherein
 the flow path member further comprises
 a plurality of fourth flow paths respectively connected to the plurality of pressurizing chambers, and 
 a fifth flow path connected in common to the plurality of fourth flow paths, and 
 
 a decimal place value of T 2 /T 0  is ⅛ to ⅞, where T 2  denotes a time required for the pressure wave to return to the one of the plurality of pressurizing chambers after being propagated from the one of the plurality of pressurizing chambers to one of the plurality of fourth flow paths and being reflected at a connection position between the one of the plurality of fourth flow paths and the fifth flow path. 
 
     
     
       4. The liquid ejection head according to  claim 1 , wherein
 the flow path member further comprises
 a plurality of fourth flow paths respectively connected to the plurality of pressurizing chambers, and 
 a fifth flow path connected in common to the plurality of fourth flow paths, and 
 
 T 1 >T 2  is satisfied, where T 2  denotes a time required for the pressure wave to return to the one of the plurality of pressurizing chambers after being propagated from the one of the plurality of pressurizing chambers to one of the plurality of fourth flow paths and being reflected at a connection position between the one of the plurality of fourth flow paths and the fifth flow path. 
 
     
     
       5. The liquid ejection head according to  claim 4 , wherein
 a length of a route of the annular flow path inside the third flow path occupies 30% or more of a length of a route of the annular flow path. 
 
     
     
       6. The liquid ejection head according to  claim 4 , wherein
 the plurality of fourth flow paths is located between the plurality of first flow paths and the plurality of second flow paths in an opening direction of the plurality of ejection holes. 
 
     
     
       7. The liquid ejection head according to  claim 1 , wherein
 the third flow path extends in a direction perpendicular to an opening direction of the plurality of ejection holes, and 
 the one of the plurality of first flow paths and the one of the plurality of second flow paths extend from the third flow path to an identical side in a width direction of the third flow path, when viewed in the opening direction. 
 
     
     
       8. The liquid ejection head according to  claim 1 , wherein
 the third flow path extends in a direction perpendicular to an opening direction of the plurality of ejection holes, and 
 the one of the plurality of first flow paths and the one of the plurality of second flow paths extend from the one of the plurality of pressurizing chambers to mutually opposite sides in a flow path direction of the third flow path and then extend to an identical side in a width direction of the third flow path, and are connected to the third flow path at mutually different positions in the flow path direction, when viewed in the opening direction. 
 
     
     
       9. A recording apparatus comprising:
 the liquid ejection head according to  claim 1 ; 
 a transport unit that transports a recording medium to the liquid ejection head; and 
 a control unit that controls the liquid ejection head.